1. Technical Field
The present invention relates generally to information processing and, in particular, to a hybrid approach for performance enhancing proxies.
2. Description of the Related Art
A fundamental problem in using Transmission Control Protocol/Internet Protocol (TCP/IP) over wireless networks is TCP's default behavior in interpreting packet losses as a sign of network congestion. While this assumption is useful in wired networks, where packet losses are mainly caused by buffering limits in routers, it causes problems in wireless networks. This is because in wireless networks, packet losses can occur due to issues such as fading, attenuation, and collisions, problems unique to using the air as the transmission channel. These packet losses can unnecessarily restrict performance, leaving the wireless channel under-utilized.
There have thus been approaches to mitigate this problem by decoupling packet loss from congestion control, through the following two approaches:    (a) modifying the end-host TCP protocol stack; or    (b) inserting a middlebox, known as a performance-enhancing proxy, close to the wireless link.
The first approach is difficult to deploy since it relies on upgrading all the clients and all the servers that utilize the wireless link, typically an extremely difficult process due to the wide variety of mobile devices and server operating systems.
The second approach is easier to deploy, since it can be done incrementally, as well as transparently to the client and server. However, the second approach, as implemented in the prior art, suffers from many deficiencies including, but not limited to, changing the semantics of the TCP connection in undesirable manners that can cause incorrect behavior by the sender.